Posts Tagged: biogenesis

Role of Exosomes in Myocardial Remodeling

Role of Exosomes in Myocardial Remodeling

Anders Waldenström, Gunnar Ronquist

Cartoon of an exosome. The exosomal contents comprise mRNA, DNA, microRNAs, proteins (ie, enzymes, growth factors, and cytokines), and transmembrane proteins of different kinds, including tetraspanins, annexin, and intracellular cell adhesion molecule. For further information, see text. Reprinted from Hu et al124 with permission of the publisher. Copyright © 2012, Frontiers in Genetics. [Powerpoint File]

Role of Exosomes in Myocardial Remodeling

Role of Exosomes in Myocardial Remodeling

Anders Waldenström, Gunnar Ronquist

Biogenesis of exosomes. Exosomes are generated in the late endosomal compartment and carry recycled proteins from coated pits/lipid rafts in the cellular membrane, proteins directly sorted to the MVBs from RER and GC, mRNA, microRNA, and DNA. Note that the generation of exosomes by inward budding of the limiting membrane of MVB ensures that the membrane-bound proteins preserve the same orientation and folding on the exosomal membrane as those on the plasma membrane. The exosome-filled MVBs are either fused with the plasma membrane to release exosomes or sent to lysosomes for degradation. Exosomes are different from ectosomes and apoptotic bodies because the latter extracellular vesicles are the result of a direct budding process of the plasma membrane. GC indicates Golgi complex; MV, microvesicle internalized from the cellular membrane, early endosomes; MVB, multivesicular body; and RER, rough endoplasmic reticulum. The role of placental exosomes in reproduction. (Illustration credit: Ben Smith). Reprinted from Mincheva-Nilsson and Baranov52 with permission of the publisher. Copyright © 2010 John Wiley & Sons A/S. Authorization for this adaptation has been obtained both from the owner of the copyright in the original work and from the owner of copyright in the translation or adaptation. [Powerpoint File]

Mitochondria and Endothelial Function

Mitochondria and Endothelial Function

Matthew A. Kluge, Jessica L. Fetterman, Joseph A. Vita

Conceptual illustration of the mitochondrial life cycle and the contribution of mitochondrial dynamics and mitophagy to quality control. Biogenesis is regulated by peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α), which activates nuclear respiratory factor (NRF)-1 and NRF-2 and transcription factor A mitochondrial (TFAM) and transcription factor B mitochondrial (TFBM). Mitochondria undergo cycles of fusion to form elongated mitochondrial networks and fission into smaller individual organelles. Fusion is mediated by mitofusin (MFN) 1, MFN2, and optic atrophy protein 1 (OPA1). Fission is mediated by dynamin-related protein-1 (DRP1) and fission 1 (FIS1). During their normal lifespan and in the setting of increased oxidative stress, damage to mitochondrial components accumulates. Fission provides a mechanism to isolate damaged components for elimination. Mitophagy involves mitochondrial depolarization, retention phosphatase and tensin homolog–induced putative kinase protein 1 (PINK1) in the mitochondrial membrane, and recruitment of Parkin, which targets the mitochondria to autophagosome. P62 also plays a role in targeting cargo to the autophagosome and is subsequently degraded during active autophagy. Assembly of the phagosome involves beclin-1 and conjugation of microtubule-associated protein 1 light chain 3 (LC3) onto phosphatidylethanolamine to form of LC3-II. (Illustration Credit: Ben Smith) [Powerpoint File]